Wenna Huang

Triple-shelled Mn2O3 hollow nanocubes: force-induced synthesis and excellent performance as the anode in lithium-ion batteries

In this paper, we report a novel structure of Mn2O3, the triple-shelled Mn2O3 hollow nanocube, as the anode material for high-energy lithium-ion batteries, synthesized through a programmed annealing treatment with cubic MnCO3 as precursor. This hierarchical structure is developed through the interaction between the contraction force from the decomposition of MnCO3 and the adhesion force from the formation of Mn2O3. The structure has been confirmed by characterization with XRD, FESEM, TEM, and HRTEM. The charge–discharge tests demonstrate that the resulting Mn2O3 exhibits excellent cycling stability and rate capability when evaluated as an anode material for lithium-ion batteries. It delivers a reversible capacity of 606 mA h g−1 at a current rate of 500 mA g−1 with a capacity retention of 88% and a remaining capacity of 350 mA h g−1 at 2000 mA g−1.

Oxidative stability and reaction mechanism of lithium bis(oxalate)borate as a cathode film-forming additive for lithium ion batteries

The oxidative decomposition mechanism of lithium bis(oxalate)borate (LiBOB) as a cathode film-forming additive has been investigated using density functional theory calculations at the B3LYP/6-311++G(d) level, with the polarized continuum model. The calculated oxidation potentials of the investigated structures decreased in the following order: carbonate (including isolate EC, PC and DMC) > BOB− (isolate) ≈ carbonate–BOB− clusters. Charge distribution results show that the electron of the oxidized carbonate–BOB− cluster was taken from BOB−, indicating the higher oxidation activity of BOB−. Decomposition mechanism analyses of the EC–BOB−-e cluster indicate that breakage of the BOB− structure is more energetically favorable than EC. The most likely reaction path of this cluster is the ring opening reaction of BOB− via two transition states, generating CO, CO2 and radical R1 which may further terminate generating a borate-containing oligomer. This oligomer is believed to play a crucial role in suppressing further oxidative decomposition of carbonate solvents.